Pro96Com NAC Decoding

[N9JIG]

I could have sworn PRO96COm decoded and displayed NAC codes, apparently it does not. Am I doing something wrong?

 

[Unitrunker2]

Some radios pass the NAC. Some don't.

 

[N9JIG]

The question was answered by Mike at the Yahoo Group, it appears that the NAC is sent on the low speed data that PRO96Com does not utilize, which explains why it can be seen on the radio but not in the software.

 

[Unitrunker2]

The question was answered by Mike at the Yahoo Group, it appears that the NAC is sent on the low speed data that PRO96Com does not utilize, which explains why it can be seen on the radio but not in the software.

That's not accurate. Not knocking Mike. Mister Van der Veer and I have exchanged tidbits for over a decade. When you are focused on control channel TSBKs (like Mike), the NAC is not important.

The NAC is 12 bits of the 16 bit DUID which is sent in the 64 bit NID just after the 48 bit frame sync pattern that starts every frame on a P25 control channel (and every frame on a P25 P1 voice channel). The streaming data from some radios (not the PRO96) include the NAC. At least one Uniden model provides it. That said, it isn't terribly important. You can program your scanner without it.

Low speed data is a whole different thing and even less interesting.

 

[slicerwizard]

The question was answered by Mike at the Yahoo Group, it appears that the NAC is sent on the low speed data that PRO96Com does not utilize, which explains why it can be seen on the radio but not in the software.

Yeah, this makes no sense. In a P25 context, low speed data refers to small fields in the LDU frames and they are never used to transmit NAC information. As noted above, every P25p1 frame already contains the NAC value in the frame header data.